(Not Applicable)
(Not Applicable)
This invention relates in general to protective cover structures, and in particular to a protective structure for both thermal insulation and impact resistance wherein thermally insulative tile is encased within an impact resistant fiber reinforced ceramic matrix composite material to thereby provide high-temperature protection inherent in tile along with impact-damage protection against high-speed particulate collisions.
The use of ceramic tile as a protective external structure is employed in various aircraft including spacecraft where thermal insulation is required for high-temperature protection against the heat of engine exhaust and of heat generated due to atmospheric re-entry. A typical aircraft application includes the bonding of a plurality of laterally juxtaposed tiles, usually square in shape, onto the aircraft. As is evident, the tiles so bonded are completely exposed and thus subject to all external environmental factors. As a result, while such tiles are highly effective in providing thermal protection, because their physical properties include a relative softness, they relatively quickly degrade due to impact forces upon collision with environmental particulate. Such deterioration results, of course, in high maintenance and product costs because frequent replacement is required to maintain the operability of the aircraft.
Despite the drawbacks associated with ceramic tile usage, no other compositions function as efficiently in providing the thermal protection that the product imparts. In view of this quality, it is apparent that a protective structure embodying ceramic tile coupled with an impact protectorant for such tile would provide an optimum combination usable in high-temperature applications and especially in aircraft applications. Accordingly, a primary object of the present invention is to provide a thermally-insulative ceramic tile structure additionally resistant to impact degradation from striking environmental particulate.
Another object of the present invention is to provide a thermally-insulative ceramic tile structure wherein impact resistance is provided from a ceramic matrix composite encasing a ceramic tile.
Yet another object of the present invention is to provide a thermally-insulative ceramic tile structure wherein a plurality of ceramic tiles are encased within one ceramic matrix composite encasement to thereby permit enlarged single structures for application to an aircraft.
These and other objects of the present invention will become apparent throughout the description thereof which now follows.
The present invention is a protective structure for thermal insulation and impact resistance, and is especially suited for bonded application to the exterior of aircraft including spacecraft to protect the craft from high temperatures generated by exhaust gases and by atmospheric re-entry. The structure comprises either a single ceramic tile component with a cover component comprising a fiber reinforced ceramic matrix composite encasing the tile component, or a plurality of ceramic tile components with a single cover component comprising a fiber reinforced ceramic matrix composite encasing the plurality of tile components. As is apparent, the latter configuration encompassing a plurality of tile components with a single encasement provides greater efficiency for application to an aircraft, for example, since a plurality can be placed at once. Conversely, the encased single ceramic tile component provides placement flexibility with respect to spacing because of being a smaller structure thereby positionable in tighter constraints.
Utilizing the present structure as an external aircraft surface imparts a super hard exterior that functions to significantly prohibit impact and erosion damage while not compromising the desirable thermal insulation properties inherent to tile. Formation of the structure is accomplished by wrapping one or more ceramic tile components within a single cover component comprising a prepreg ceramic matrix composite to thereby produce a precursor of the protective structure. This precursor is then subjected to a curing process, herein defined as including pyrolysis, to thereby render the prepreg composite as a fired ceramic matrix composite encompassing the ceramic tile component (s). Conventional tile adhesives can be employed to bond the structure at desired sites of the aircraft to thereby accomplish thermal protection while simultaneously protecting against foreign object impact. These benefits result in a more rapid turnaround of aircraft accompanied by significantly lower maintenance and operating costs.